Major resources of a computer and their performance-determining factors

Primary memory

Capacity

Higher is better. The maximum capacity per memory module is 32 GB for desktop computers, 16GB for laptops. But memory with this high capacity is only developed recently, and therefore is very expensive. 16GB per module for desktop computers and 8GB per module in laptops are more affordable.

Number of channels

Modern processors usually support multi-channel memory architecture. Double the number of channels also double the memory bandwidth. Generally, the number of channels supported depends on the number of cores of CPU. For example, the Intel U series processors which are commonly used in ultra-books and have 2 cores, support up to 2 memory channels. Intel HQ, T, K series have 4 cores, and therefore support up to 4 memory channels.

Frequency:

The higher the frequency is, the greater the bandwidth. The common frequency for DDR3 (or LDDR3, the low voltage version) memories is 1333MHz and 1600MHz, while that for DDR4 memories is 2133MHz and 2400MHz. DDR4 memories are only widely used after 2015, and now they are supported by family Intel 6th Generation processors, and also future generations.

Secondary storage

For HDD (hard disk drives):

The number of disks

Double the number of disks doubles the capacity, and also the IO speed.

RPM (round per minute):

5400rpm HDDs are the most common. However, their performance is lower than those 7200rpm HDDS. HDDs with 10000rpm and above are only used in servers. Note that although the performance is proportional to the RPM, the stability decreases with the increase of RPM. High RPM HDDs are more likely to be damaged when in vibration.

Processor speed

Core clock

The frequency of a core. The performance of CPU is proportional to its core clock

Number of Cores

Theoretically, the performance of CPU will be doubled if the number of cores doubles, assuming that the programs have multi-core support.

Size of Cache

Larger is better. Usually, the CPU manufacturer will make its capacity reasonable. The capacity of cache required is proportional to the number of cores.

Network connectivity

Bandwidth

Higher is better, usually measured in Mbps. Note that 8Mb = 1Mib. The bandwidth for wired network ranges from 10Mbps to 1000Mbps. The most common bandwidth supported by mainstream routers is 100Mbps.

For wireless, the bandwidth depends on the protocol and utilization of MIMO (Multiple input multiple output).
802.11b/g/n/ac supports 11, 54, 150, and 433Mbps bandwidth, respectively. By MIMO, the bandwidth can be doubled/tripled/quadrupled.

Ping

The delay of data transmission, measured in milliseconds. Lower is better.

Screen resolution

Higher is better. The quality of the display also depends on the pixel density, measured by the PPI (pixels per inch)

Graphics processor

CUDAs

The number of parallel workers in the GPU. Higher is better.

GPU core frequency

Higher is better

Graphical memory capacity

Higher is better.

Graphical memory frequency